It is simple to install, and can be run on a schedule via cron, or via a LaunchDaemon on OS X. One notable difference from my Jira to OmniFocus integration is that this script puts the body of the GitHub issue into the Note of the OmniFocus task. This feature may be coming as an enhancement to the Jira integration soon.

If you have any problems or enhancement requests please create a GitHub issue on the project. Thanks!